The amateurization of networked photographic equipment, or the prevalence of multifunctional video software such as VLC Media Player, has empowered a growing number of people to become content providers. Meanwhile, the Internet architecture based on TCP/IP (Transmission Control Protocol/Internet Protocol) has been so intricately developed that in the wake of the ubiquity of routers capable of network address translation (NAT), it is still frustrating for the public to configure a device on a local area network (LAN) in such a way that the device is able to passively accept connection from outside the LAN. Consider an IP camera, whose real-time image output is typically advertised as accessible anytime, anywhere after successful installation of the camera and configuration of port forwarding in the router. If, however, the camera is on a LAN, and the user is not authorized to administrate the router or firewall of the LAN or does not even know what a LAN is, the advertised benefits are by all means an illusion. Even if there were some NAT traversal mechanism in place or proxy or relay servers set up for the camera and the corresponding image receiving device, there would be no guarantee of stable establishment of a peer-to-peer or point-to-point connection, not to mention the significant amount of time wasted attempting the optimal mode of connection over and over again.